Leucocyte-depleted blood: a comparison of cell-washing techniques

Non-haemolytic febrile transfusion reactions are common in multi-transfused patients. It is generally accepted that the majority of these reactions occur when more than 0.5 x 10(9) leucocytes are transfused. Values equal to or lower than this threshold, which we have called for convenience the critical antigenic load for leucocytes (CALL), can be achieved by decreasing the leucocyte content in one unit of whole stored blood by about 80%. We have compared the efficiency of leucocyte depletion of whole stored blood, using fixed-speed centrifugation (Haemonetics Model 15 and Model 115 cell washer), variable-speed centrifugation (Dideco Progress 90 Cell Separator), and serial centrifugation (IBM 2991 Blood Cell Processor. Fixed-speed centrifugation was least effective in depletion leucocytes; a reduction of 25 and 60% was achieved using the Haemonetics Model 15 and Model 115, respectively. Variable speed and serial centrifugation produced more satisfactory results with leucocyte depletions of 82 and 89% using the Dideco Progress 90 Cell Separator and the IBM 2991 Blood Cell Processor, respectively. Platelet depletion of over 90% was achieved with all the cell washers, except the Haemonetics Model 15. Red cell losses varied from 3 to 30%. It seems unlikely that consistently high (over 90%) leucocyte depletion can be obtained using cell-washing techniques without associated high red cell losses.